Add additional logic to redacting sensitive content

Only show the redacted sensitive content view if:
1. the device is locked
2. it has been locked for over 10 minutes
3. the device hasn't been unlocked since the notification came in

Test: atest NotificationLockscreenUserManagerTest
Bug: 358403414
Fixes: 383905441
Flag: android.app.redact_sensitive_content_notifications_on_lockscreen
Change-Id: I89d4c2781d60d5e11fc7e7b94d904bea00cc7cd5